(a) Field of the Invention
The present invention relates to a transfer-pattern thin film fabrication method. More particularly, the present invention relates to a method for making a transfer-pattern thin film that assures quality consistency, improves manufacturing efficiency and lowers the manufacturing cost.
(b) Description of the Prior Art
As illustrated in FIGS. 1 and 2, an in-mold transfer-printing film or a transfer-printing thin film comprises a hard coat layer 10, an ink layer 20 coated or printed on the hard coat layer 10, a metal layer 30 coated on the ink layer 20 opposite to the hard coat layer 10, an adhesive layer 40 coated on the metal layer 30 opposite to the ink layer 20, a release layer 50 covered on the hard coat layer 10 opposite to the ink layer 20 and the release layer 50 covered on a thin-film substrate 60.
During IMD (in-mold decoration) transfer printing application, the adhesive layer 40 of the transfer-printing thin film or in-mold transfer-printing film is bonded to the surface of a plastic or metal member, for example, a cell phone cover or a notebook cover. By means of the release layer 50, the thin-film substrate 60 can be separated from the rest of the transfer-printing thin film or in-mold transfer-printing film, leaving the hard coat layer 10, the ink layer 20, the metal layer 30 and the adhesive layer 40 on the plastic or metal member so that the plastic or metal member has a smooth surface that carries a design. The term “hard coat layer 10” is so called because it generally provides a relatively hard outer surface layer (i.e. coat) for the plastic or metal member after the thin-film substrate 60 is separated with the release layer 50. In the following description, the material making up the hard coat layer 10 is called the “hard coat layer material” or “hard coat material” and the material making up the release layer is called the “release layer material” or “release material”.
According to the aforesaid prior art design, the release layer 50 is coated on the surface of the thin-film substrate 60, the hard coat layer 10 is coated on the surface of the release layer 50. The fabrication is complicated because two separate steps must be performed to have the release layer 50 and the hard coat layer 10 covered on the thin-film substrate 60. Further, because the release layer 50 has a thickness within 1 μm˜2 μm, the release layer 50 tends to be damaged during the manufacturing process, thus affecting product quality.
Therefore, it is desirable to provide a method for making a transfer-pattern thin film that eliminates the aforesaid problems.